Fan base



FIG. 1 is a top perspective view of a fan base showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof; and,

FIG. 6 is an unobstructed top plan view thereof.

The broken line showing of environmental structure in FIGS. 1-5 is for illustrative purposes only and forms no part of the claimed design.

The bottom view and back view form no part of the claimed design. 

The ornamental design for a fan base, as shown and described. 